Ultrasonic surgical instruments are finding increasingly widespread applications in surgical procedures by virtue of the unique performance characteristics of such instruments. Depending upon specific instrument configurations and operational parameters, ultrasonic surgical instruments can provide substantially simultaneous cutting of tissue and hemostasis by coagulation, desirably minimizing patient trauma. The cutting action is typically effected by an end-effector at the distal end of the instrument, with the end-effector transmitting ultrasonic energy to tissue brought into contact therewith. Ultrasonic instruments of this nature can be configured for open surgical use, or laparoscopic or endoscopic surgical procedures.
Ultrasonic surgical instruments have been developed that include a clamp mechanism to press tissue against the end-effector of the instrument in order to couple ultrasonic energy to the tissue of a patient. Such an arrangement (sometimes referred to as an ultrasonic transector) is disclosed in U.S. Pat. No. 5,322,055, hereby incorporated by reference.
Heretofore, various configurations have been known for the ultrasonic end-effector of the above type of clamp coagulator apparatus, and the associated pivotal clamp arm. By these various configurations, optimization of the manner in which tissue is coupled to the end-effector, or "blade", has been sought, with efforts to particularly achieve the desired degree of cutting and concomitant coagulation. At the same time, precise and efficient use of such instruments is facilitated by configuring the clamp arm and end-effector to cooperate for efficient tissue gripping.
Experience has shown that formation of a clamp arm with teeth which effect the desired gripping can result in the teeth acting as energy directors, which cut tissue quickly without allowing adequate time for coagulation. On balance, positioning the teeth to abate this effect can result in inadequate tissue grasping.
The present invention is particularly directed to an improved clamp arm arrangement, including a tissue pad having a plurality of axially spaced teeth which define a tissue-gripping surface configured for enhanced gripping and ultrasonic effect.